Damper

ABSTRACT

A damper has a body, a spindle and multiple beads. The body has a base with a through hole, a top cap with a through hole and a cavity defined in the body. The spindle is mounted inside the body and has a spindle body and a transverse post formed on the spindle body. The multiple beads are received inside the cavity in the body and abut the transverse post. The damper provides a friction by the transverse post abutting and moving over the beads, therefore, when the damper is mounted on a retractable device, the retracting rate of the retractable device may be adjusted conveniently by changing the amount of the beads.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a damper, and more particularly to a damper adapted for a retractable device.

2. Description of Related Art

Many devices have retractable devices mounted inside, the devices, such as electric wire retractor, retractable tape, window curtains or seat belt of the car, provide a retractable force for pulling a string or a belt back. The retractable device has a spiral spring mounted inside, when a foreign force pulls the spiral spring out, the spiral spring will return back automatically when the force is released.

The spiral spring provides a retractable force for the string or the belt, and has the following advantages. First, the spiral spring provides a constant resilience. Second, the distance for retracting the spiral spring is short. Therefore, the volume of the spiral spring is small, and such spring is very convenient for use.

However, the coefficient of elasticity k value of the spiral spring relates to the rate for retracting a string or a belt, i.e. the coefficient of elasticity k value of the spiral spring relates to the retractable force of the spiral spring and whether the spiral spring retracts smoothly. When the coefficient of elasticity k value is small, the retractable force is small so that a string or a belt may not be retracted completely. When the k value is large, the force for retracting a string or a belt will be large and a string or a belt may wind around or make somebody get hurt caused by a fast retracting movement.

To overcome the shortcomings, the present invention tends to provide a damper to mitigate the aforementioned problems.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a damper that is applied to a retractable device and improves the safety of using the retractable device.

The damper has a body, a spindle and multiple beads. The body has a base with a through hole, a top cap with a through hole and a cavity defined in the body. The spindle is mounted inside the body and has a spindle body and a transverse post formed on the spindle body. The multiple beads are received inside the cavity in the body and abut the transverse post.

The damper provides a friction by the transverse post abutting and moving over the beads, therefore, when the damper is mounted on a retractable device, the retracting rate of the retractable device may be adjusted conveniently by changing the amount of the beads.

Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a first embodiment of a damper in accordance with the present invention;

FIG. 2 is a side view in partial section of the damper in FIG. 1;

FIG. 3 is a side view in partial section of a retractable railing device with the damper in FIG. 1;

FIG. 4 is a perspective view of the retractable railing device with the damper in accordance with the present invention;

FIG. 5 is a perspective view of a retractable tape with the damper in accordance with the present invention;

FIG. 6 is a perspective view of an electric appliance with the damper in accordance with the present invention; and

FIG. 7 is a side view in partial section of a retractable railing device with a second embodiment of a damper in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, a first embodiment of a damper (A) in accordance with the present invention has a body (10), a spindle (20) and multiple beads (30).

The body (10) has a base (11), a top cap (12) and a cavity (13). The base (11) has a through hole (111) defined therein. The top cap (12) is mounted on the base (11) and has a through hole (121) corresponding to the through hole (111) in the base (11). The cavity (13) is defined between the base (11) and the top cap (12).

The spindle (20) is mounted inside the body (10) and has a spindle body (200) and a transverse post (21). The spindle body (200) has a top end, a bottom post and a sidewall. The top end of the spindle body (200) is mounted inside the through hole (121) in the top cap (12), and the bottom post of the spindle body (200) is mounted through the through hole (111) in the base (11). In a preferred embodiment, the bottom post is a non-circular post and may be a hexagonal post. The transverse post (21) is formed on the sidewall of the spindle body (200) and is received inside the cavity (13) in the body (10).

The bead (30) are received inside the cavity (13) in the body (10) and abut the transverse post (21). The beads (30) may be made of steel, plastic, or any material.

With reference to FIGS. 3 and 4, when a damper (A) is used for a retractable railing device (40), the retractable railing device (40) has a post body (400), a spiral spring (41), a railing (42) and a spindle (43). The post body (400) has a top, a mounting hole (401) and a central cavity. The mounting hole (401) is defined in the top of the post body (400). The central cavity is defined in the post body (400). The spiral spring (41) is mounted on the post body (400) for providing a retractable force to the railing (42). The spindle (43) is mounted inside the central cavity in the post body (400) and has a top. The top of the spindle (43) is mounted with and through the spiral spring (41) and is held inside the mounting hole (401) in the post body (400). The top of the spindle (43) has a non-circular hole. In a preferred embodiment, the hole in the top of the spindle (43) is non-circular and may be a hexagonal hole for receiving the bottom post of the spindle (20). The railing (42) is rolled around the spindle (43). The damper (A) is mounted on the top of the post body (400). The bottom post of the spindle body (200) is partially mounted inside the mounting hole (401) and aligned with the spindle (43).

When the retractable railing device (40) is used, and the spindle (43) is driven to rotate by the spiral spring (41) to pull the railing (42) back. The spindle (20) of the damper (A) is then driven by the spindle (43) of the retractable railing device (40) with the engagement between the bottom post on the spindle (20) and the hole in the spindle (43).

When the spindle (20) rotates, the beads (30) will block the rotation of the transverse post (21) so as to provide a drag effect to the spindle (20). Therefore, the speed of retracting the railing (42) is reduced, and the retracting rate provided by the spiral spring (41) is effectively damped. In addition, the amount of the beads (30) and the retracting rate of the retractable railing device (40) are in an inverse proportion. When the amount of the beads (30) is decreased, the damper (A) provides a less drag effect to the retractable railing device (40). When the amount of the beads (30) is increased, the damper (A) provides a large drag effect to the retractable railing device (40). Therefore, the damper (A) may control the retractable rate effectively by changing the amount of the beads (30) inside the damper (A).

With reference to FIGS. 5 and 6, the damper (A) may be applied to different retractable devices, such as a retractable tape (70), an electric appliance (80) with electric wire retractor or any retractable device like window curtains or seat belt in a vehicle. Each retractable device has a spindle for holding the spindle (20) of the damper (A). A person skilled in the art will understand how to employee the invention on a retractable device.

With reference to FIG. 7, a second embodiment of a damper (B) is adapted for a retractable railing device (60). The retractable railing device (60) has a post body (600), a spiral spring (61), a railing, a spindle (63) and a damper (B). The post body (600) has a top and a central cavity. The central cavity is defined in the post body (600). The spindle (63) is mounted inside the central cavity in the post body (600) and has a top end and a non-circular hole defined in the top end of the spindle. The railing is rolled around on the spindle (63). The spiral spring (61) is mounted inside the central cavity in the post body (600). The damper (B) is mounted on the post body (600) and has a base (62), a top cap (621), a cavity (622), a spindle (20) and multiple beads (30). The base (62) is mounted on the top of the post body (600). The top cap (621) is mounted on the base (62). The cavity (621) is defined between the top cap (621) and the base (622). The spindle (20) is mounted on the spindle (63) inside the post body (600) and passes through the spiral spring (61) and has a transverse post (21) and a bottom post both formed on the spindle (20) as described above. The bottom post is a non-circular post mounted on the spindle inside the central cavity in the post body (600). The multiple beads (30) are received inside the cavity (622). Therefore, when the railing is pulled back by the spiral spring (61), the transverse post (21) abutting the beads (30) and limits the rotating rate of the spindle (20), so the retractable rate of the railing driven by the spindle (63) will be limited by the damper (B).

The advantages of the damper of the present invention describe as follows.

1. The damper (A, B) provides a friction by means of the transverse post (21) abutting and moving over the beads (30), therefore, the retracting rate of the retractable railing device will be reduced.

2. When the damper (A, B) is applied for a coefficient of elasticity k value device, the device may retract a heavy cord at a lower speed and smoothly.

3. When the retracting rate is reduced, a retractable device will be used safer and prevents a person from getting hurt. In addition, if the coefficient of elasticity k value of the spiral spring (61) is kept at a constant, the retracting force provided by the spiral spring (61) for retracting an object will not be changed even when the damper (A, B) is applied. Therefore, whether the transverse post (21) stops abutting the beads (30) or not, the retracting force provided by the spiral spring is constant.

4. The retracting rate is adjusted by changing the amount of the beads, so it is convenient for adjusting the friction providing by the damper (A, B).

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A damper comprising: a body having a base having a through hole, a top cap mounted on the base and having a through hole corresponding to the through hole in the base, and a cavity defined in the body between the base and the top cap, a spindle mounted inside the body and having a spindle body mounted inside the body having a top end mounted inside the through hole in the top cap, and a bottom post mounted through the through hole in the base, a transverse post formed on the spindle body and received inside the cavity in the body, and multiple beads received inside the cavity in the body and abutting with the transverse post.
 2. The damper as claimed in claim 1, wherein the multiple beads are made of steel.
 3. The damper as claimed in claim 1, wherein the multiple beads are made of plastic.
 4. A retractable railing device with a damper comprising a post body having a top, a mounting hole defined in the top of the post body, and a central cavity defined in the post body, a spindle mounted inside the central cavity in the post body and having a top mounted with and through the spiral spring, held inside the mounting hole in the post body and having a non-circular hole, and a spiral spring mounted on the top of the spindle for providing a retractable force, a railing rolled around the spindle, and a damper mounted on the post body and having a body having a base mounted on the top of the post body and having a through hole, a top cap mounted on the base and having a through hole corresponding to the through hole in the base, and a cavity defined in the body between the base and the top cap, a spindle mounted inside the body and having a spindle body having a top end mounted inside the through hole in the top cap, a bottom post being a non-circular post, mounted through the through hole in the base, mounted in the non-circular hole in the top of the spindle, a transverse post formed on the spindle body and received inside the cavity in the body, and multiple beads received inside the cavity in the body and abutting the transverse post.
 5. The retractable railing device as claimed in claim 4, wherein the multiple beads are made of steel.
 6. The retractable railing device as claimed in claim 4, wherein the multiple beads are made of plastic.
 7. A retractable railing device with a damper comprising a post body having a top, and a central cavity defined in the post body, a spindle mounted inside the central cavity in the post body and having a top end, and a non-circular hole defined in the top end of the spindle, a spiral spring mounted inside the post body for providing a retractable force, a railing rolled around the spindle, and a damper mounted inside the post body and having a base mounted on the top of the post body and having a through hole, a top cap mounted on the base and having a through hole corresponding to the through hole in the base, a cavity defined between the top cap and the base, a spindle mounted on the spindle in side the post body and passing through the spiral spring, having a top end mounted inside the through hole in the top cap, a bottom post being a non-circular post and mounted through the through hole in the base, mounted in the non-circular hole in the top end of the spindle, and a transverse post formed on the spindle received inside the cavity in the body, and multiple beads received inside the cavity in the body and abutting the transverse post.
 8. The retractable railing device as claimed in claim 7, wherein the multiple beads are made of steel.
 9. The retractable railing device as claimed in claim 7, wherein the multiple beads are made of plastic. 